As well known, according to the rapid increase in traffic volume due to economic growth and increased income, and according to the tendency toward high-speed road traffic due to the improvement in the performance of vehicles, the incidence of traffic accidents has increased. As well, the scale of a traffic accident has also increased, thus resulting in enormous national and social loss. Furthermore, according to statistics, the number of single-vehicle accidents has rapidly increased. Therefore, the maintenance of roadside equipment and the installation of protective structures are required, as has been demonstrated by the results of extensive research.
A guard rail and an impact absorbing apparatus, which is provided in front of the guard rail to absorb the impact of vehicle collision, are representative examples of such protective structures.
The guard rails are installed on both sides of a road or on the central line of the road and thus define the width of the road, within which vehicles travels. In addition, when a vehicle undesirably moves off the road, the guard rails serve to protect passengers and the vehicle from dangers present beside the road, and guide the vehicle in a direction in which the vehicle can remain safe, in order to prevent a chain accident involving following vehicles and thus prevent the passengers and the vehicles from being injured and damaged. The vehicle collision impact absorbing apparatuses for roads are installed in front of the guard rails or concrete structures and serve to absorb the impact when vehicles collide with the guard rails or the concrete structures.
However, in the case of the vehicle collision impact absorbing apparatuses according to conventional techniques, because they are constructed such that only about five to ten scrap tires, which are tied together, are placed in front of a guard rail or a concrete structure, there is a problem in that secondary safety hazards may be induced.
That is, because the scrap tires are merely placed in front of the guard rail or the concrete structure and are not fixed thereto, when a vehicle collision occurs, the scrap tires may fly away from their original positions and impede the travel of other vehicles. Furthermore, the material of the scrap tires is unsuitable for slowly absorbing impacts. Hence, even if the scrap tires are fixed to the guard rail or the concrete structure, there is a problem in that the vehicle may rebound from the scrap tires, with the result that it collides with another vehicle.
In an effort to overcome the problems experienced with the conventional techniques, a vehicle collision impact absorbing apparatus, which uses scrap tires and is constructed such that, when a vehicle collision occurs, a front partition is moved backwards and an anchor thereof is locked to a locking slot of a ladder, so that the ladder is prevented from being moved in the reverse direction by the restoring force of the scrap tires, was proposed in Korean Utility Model Registration Nos. 390585 and 412263, which was filed by the applicant of the present invention and has been registered. This technique will be briefly explained herein below with reference to FIGS. 1 and 2.
As shown in FIG. 1, in the vehicle collision impact absorbing apparatus according to these techniques, two rails 1 are fixed to the ground using anchor bolts (not shown). A ladder 2, which has therein slots 2a formed at positions spaced apart from each other at regular intervals, is provided between the rails. Support guides 3a, which are provided on the lower ends of partitions 3, are inserted into the respective rails 1. As shown in FIG. 2, scrap tires 4 are interposed between the adjacent partitions 3. As seen in FIG. 2, the rightmost partition 3 is disposed on the right ends of the rails 1 and is supported by a support plate 3b such that it is prevented from being pushed off of the right ends of the rails 1.
As shown in FIGS. 1 and 2, an anchor 3c is provided on the lower end of each of the first and second partitions 3, counting from the left end of the rails. Thus, when a vehicle collision occurs, the anchors are locked to corresponding slots 2a of the ladder 2. The functions of the ladder 2, the anchors 3c, the scrap tires 4 and openings 4a, which are shown in FIGS. 1 and 2, are described in detail in Korean Utility Model Registration Nos. 367001, 376121 and 390585, which were filed by the applicant of the present invention, therefore further explanation will be skipped.
Referring to FIG. 1, locking holes 2b are formed on opposite positions of the slot 2a, which is formed through the rear end of the ladder 2, so that locking parts of catches 5a of a ladder holding device 5 are inserted into and locked to the respective locking holes 2b. The detailed explanation of the ladder holding device 5 and a roller 6 will be skipped, because it was provided in detail in Korean Utility Model Registration No. 412263.
However, in the conventional vehicle collision impact absorbing apparatus having the above-mentioned construction, because a relatively large collision force is applied from the left of FIG. 2 to the partitions 3 when a vehicle collides with the apparatus, even though the scrap tires 4 are used, the impact absorbing apparatus cannot satisfactorily absorb the momentary force.
In other words, even though the contractile force of the scrap tires is used, when a relatively large momentary force is applied to the impact absorbing apparatus, the partitions 3 are moved backwards too rapidly. Thereby, the impact absorbing apparatus itself may become damaged, thus becoming useless.
Therefore, a structure in which, when a vehicle collision occurs, partitions can slowly move to satisfactorily absorb the collision force of the vehicle, rather than moving rapidly, is required.
Furthermore, in the technique of FIG. 1, the ladder holding device 5 is constructed such that, after the vehicle collision occurs, the ladder 2 is released from the ladder holding device 5 by manually rotating a lever 7, which is integrated with a shaft rod 7a, and the scrap tires 4, which have been contracted, are thus returned to the original positions thereof. However, in the case where the impact absorbing apparatus is disposed on a shoulder of a road, anybody can easily touch the lever 7. Therefore, there is a problem in that, after a vehicle collision occurs, if somebody touches the lever 7 without caution so that the scrap tires are abruptly returned to the original positions thereof, another safety hazard may result.
To solve these problems, a vehicle collision impact absorbing apparatus using a guide rod and a braking means was proposed in Korean Utility Model Registration No. 424297, which was filed by the applicant of the present invention and has been registered. This technique will be briefly explained herein below.
The impact absorbing apparatus of Korean U.M. Registration No. 424297 has the construction shown in FIG. 3. In FIG. 3, the same reference numerals as those of FIG. 1 denote corresponding parts, therefore further explanation of those parts will be skipped.
As can be understood from FIG. 3, a partition moving speed control member 10, which has an inner hole 10a having a predetermined inner diameter, is fastened to a frontmost partition 3, which is disposed at the frontmost position, with which a vehicle collides, using bolts 11 shown in FIG. 4. The guide rod 20 is inserted into the inner hole 10a of the partition moving speed control member 10. The front end of the guide rod 20 is fastened to the front ends of rails 1. A guide rod insert hole 31 for insertion of the guide rod 20 and bolt insert holes 31 for insertion of the bolts 11 are formed through the partition 3 for installation of the guide rod 20.
As shown in FIG. 4, the front end of the guide rod 20 is curved and fastened to an inclined plate 40, which is provided on the front ends of the rails 1, using brackets 41 and 42 and a bolt 43. A plurality of through holes is formed through each of the bracket 43 and the inclined plate 40. As shown in the enlarged view of FIG. 3, a bolt hole 42a is formed in the bracket 42.
FIG. 5 illustrates a tool 50, which is used to release the ladder holding device 5 from locking holes 2b of the ladder 2 after a vehicle collision occurs and thus restore the scrap tires 4, which have been contracted when the vehicle collision occurs. Two coupling holes 7b are formed in a shaft rod 7a of the ladder holding device 5, and two coupling protrusions 50a, which are inserted into the respective coupling holes 7b, are provided on the tool 50. Therefore, when it is desired to release the ladder holding device 5, the coupling protrusions 50a of the tool 50 are inserted into the respective coupling holes 7b, and the tool 50 is thereafter rotated, thus rotating the ladder holding device 5.
Referring to FIG. 6, the vehicle collision impact absorbing apparatus can be installed, for example, on an on/off ramp of a road. FIG. 7 is a sectional view illustrating the impact absorbing apparatus, which is installed as explained above.
As shown in FIG. 7, the guide rod 20 extends from the first partition, counting from the left ends of the rails, to the third partition. That is, in the impact absorbing apparatus, because the scrap tires 4 are not completely contracted from the front surface (the leftmost end) thereof to the rear surface thereof, the length of the guide rod 20 is less than that of the impact absorbing apparatus.
In a state in which the impact absorbing apparatus is installed on the on/off ramp, when a vehicle collides with the impact absorbing apparatus in the direction of the arrow of FIG. 8, the scrap tires 4 are contracted. At this time, air present in the scrap tires 4 is discharged outside through openings 4a. Simultaneously, inclined parts of anchors 3c, which are provided on the lower ends of the first and second partitions 3, counting from the left in FIG. 3, consecutively pass over several slots 2a of the ladder 2. The intensity of this process is determined by the collision force of the vehicle.
Thereafter, when the vehicle that collides with the impact absorbing apparatus is stopped, locking surfaces of the anchors 3c are locked to the corresponding slots 2a, so that the scrap tires 4 maintain the contracted state, as shown in FIG. 9. Therefore, this technique can prevent the vehicle or a person from being secondarily damaged or injured by secondary movement (expansion after contraction) of the scrap tires 4.
However, the technique of Korean U.M. Registration No. 424297 can absorb some impact, but there may be a severe defect when it is implemented at a desired place.
In detail, in this technique, as shown in FIG. 7, the guide rod 20 does not extend to the rearmost partition when the impact absorbing apparatus is initially installed (before a vehicle collides therewith). Thus, when a vehicle collision occurs, as shown in FIG. 9, while the partition moving speed control member 10 moves along the guide rod 20, the guide rod 20 is lengthened by a distance corresponding to a portion 20a, that is, by approximately 150 mm to 200 mm. At this time, the guide rod 20 may be stuck to one of the medial partitions and thus break.
In this case, it is not easy to return the partitions to the original positions thereof after clearing up the vehicle collision. Therefore, there is a problem in that it is very difficult to return the impact absorbing apparatus to the original state thereof to reuse it.